Overview

This presentation covers the following concepts

• Getting started with Git and Github

• The basics of version control systems

• Using Git and Github for collaborative software development

Getting Started with Git & Github

What is Git?

• A decentralized version control system that's free and open source

• An excellent way to track and coordinate file changes among many people

• A filing system for every draft of a document

• A tool invented by Linus Torvalds (and the Linux development community) to develop the Linux kernel in 2005

• The most widely used modern version control system in the world -- by far

• Free software distributed under the terms of the GNU General Public License version 2

• While mainly used for code, Git can be used to manage any type of file/project

  • Word documents

  • Final Cut projects

  • The entire volume of German federal laws

What is GitHub?

• A code sharing and publishing service

• A social networking site for programmers

• The single largest web-based service for hosting Git repositories

• A popular way to collaborate on code (no more emails and zip files!!)

  • The development versions of many R packages are hosted on GitHub: https://github.com/tidyverse/ggplot2

  • All the cool kids are using it!

• Includes several features beyond command-line Git

  • A Web-based graphical interface

  • Task/project management tools

  • A martketplace of integrations for many 3^rd party services

  • Issues!

  • Forking!

Why Should You use Git and GitHub?

For a fast, easy, and stress-free workflow

Your workflow - without Git

Your workflow - with Git

• Workflows without Git typically consist of

  • Lots of File renaming
  • Absurd folder structures
  • Zipped folders
  • E-mailing files back and forth
  • Lost files
  • Shared directories (one-at-a-time)
  • Ever try merging MS Word files with tracked changes?!

OK, I'm interested in using Git/Github how do I get Started

Installing Git

Configuring Git

Setting up a GitHub account

Version Control Systems

The Basics of Version Control Systems

• Before getting too deep into Git, let's take a step back

• Git is one of many different version control systems (VCS)

• It's important to understand what a VCS is and the different types of VCS that exist

What are version control systems?

Why should some use a version control system?

What is a Centralized Version Control System (CVCS)?

What is a Decentralized (aka Distributed) Version Control System (DVCS)?

What are the advantages of using a DVCS instead of a CVCS?

Using Git

Is Git hard to learn?

• New users often struggle with understanding how to use Git

• This misunderstanding is driven by the fact that there seems to be an endless number of use cases

• Git's not hard to learn -
  • There are problem

Using Git

Methods of Using Git

• There several Methods for using Git

  • At the command line
  • Within an IDE (e.g. RStudio)
  • From one of several Git desktop GUI

  • Super secret hybrid method

Which method should you choose?

• At the command line

  • Simplest (really!) & fastest
  • Works the same on Windows, Mac, and Linux

• Within an IDE (e.g. RStudio)

  • Convenient when building R packages
  • Can be clunky to update many files

• From a Git desktop GUI

Installing Git

Installing Git (Mac/linux/unix)

• For Mac, Linux, and Unix users

  • Download Git from https://git-scm.com/downloads.
  • Accept the installation defaults for your particular operating system

Installing Git (windows)

• For Windows users

  • Download Git from https://git-scm.com/downloads.
  • Accept the installation defaults EXCEPT Choose Use Git Bash

Setting Git up for the first time

• After Git has installed

  • You need modify the global configuration file to tell Git who you are.
  • Open a terminal or Git Bash (Windows) and enter the following two lines: (with the obvious modifications)

$ git config --global user.name "Brandon Greenwell" $ git config --global user.email greenwell.brandon@gmail.com

• Since you passed the option --global, you only need to do this once!

The basic process

• Initialize Git version tracking in a directory
• Add or edit files in the directory
• Check the status of file changes in the directory
• Add changed files to the staging area
• Commit one or changed files to be updated
• Push commits to the master

The basic commands you'll use/need

• cd (change directories)
• git init (initialize a folder as a Git repo)
• git add <file-name> (start tracking a new file)
• git commit -m "fix typo" (commit your changes)
• git clone (clone/copy another Git repo [e.g., from GitHub])
• git push origin master (push your master branch to your origin server)
• git pull origin master (update your local repo) Tip: Typing git add --all will start tracking everything (this is how I almost always use git add).

Using Git commands

• Initialize a repo in an existing directory

  • Create a new folder called arithmetic anywhere on your computer (e.g., the Desktop)
  • In this folder, create a new R script file called add.R
  • In this new file add the following code

add <- function(x, y) { x * y }

Initializing a repo in an existing directory

• Next, open a terminal or Git Bash (Windows) and go to the project's root directory

• For example, the code below takes me to the folder called arithmetic on my Desktop

cd C:/Users/greenweb/Desktop/arithmetic

• Then, to initialize this as a Git repo, just type

git init

Tip: the command line has a history (just like the R console), so you don't need to type as often; just hit the up arrow and make any necessary changes!

Initializing a repo in an existing directory

If you want to start version controlling all the files, you need to start tracking them. In the terminal, type the following:

then type:

How to use Git

• Free book on the Git website: https://git-scm.com/book/en/v2

GitHub

Account setup and configuration

The first thing you need to do is set up an account: https://github.com/

Use the same e-mail address you used when setting up Git!

Set up your profile

Creating a new repo

Creating a new repo

Creating a new repo

Creating a new repo

Creating a new repo

Refresh your browswer and see if it worked!

Making changes and pushing them to GitHub

Fix the obvious typo in add.R. Then, take a snapshot (i.e., git add/commit) and push the changes to GitHub (i.e., git push)!

Refresh your browser to see the changes.

Tip: It's good practice to do this every time you make a key change (e.g., fix a typo, add a new function to an R script, etc.).

* Make sure you're in the right directory!

All done!

Any questions?